1. Field of the Invention
The present invention relates to a nonvolatile memory for managing files recorded on a memory card using a FAT (File Allocation Table). In addition, the present invention relates to a nonvolatile memory reproducing apparatus for reproducing data from the nonvolatile memory, and a method thereof.
2. Description of the Related Art
EEPROM (Electrically Erasable Programmable ROM) that is an electrically rewritable memory requires a large space because each bit is composed of two transistors. Thus, the integration of EEPROM is restricted. To solve this problem, a flash memory that allows one bit to be accomplished with one transistor using all-bit-erase system has been developed. The flash memory is being expected as a successor of conventional record mediums such as magnetic disks and optical discs.
A memory card using a flash memory is also known. The memory card can be freely attached to an apparatus and detached therefrom. A digital audio recording/reproducing apparatus that uses a memory card instead of a conventional CD (Compact Disc: Trademark) or MD (Mini Disc: Trademark) can be accomplished.
A file management system used for a conventional personal computer is named FAT (File Allocation Table). In the FAT system, when a particular file is defined, predetermined parameters are successively set to the file. Thus, the size of a file becomes variable. One file is composed of at least one management unit (sector, cluster, or the like). Data corresponding to the management unit is written to a table referred to as FAT. In the FAT file system, a file structure can be easily formed regardless of the physical characteristics of a record medium. Thus, the FAT file system can be used for a magneto-optical disc as well as a floppy disk and a hard disk. In the above-mentioned memory card, the FAT file system is used.
In the conventional FAT file system, once the FAT is destroyed, it cannot be almost recovered. Thus, as possible countermeasures, it is necessary to backup data to another medium. Among users of personal computers, such countermeasures are essential. Thus, the users should backup data as their responsibilities. However, it is troublesome for the users to backup data. In addition, to do that, another medium is required.
Therefore, an object of the present invention is to provide a nonvolatile memory, a data apparatus, and a method that allow a file to be recovered even if a file management table is destroyed without need to make a backup file.
A first aspect of the present invention is a nonvolatile memory for segmenting a signal data file into blocks each having a predetermined length and adding an attribute file for managing the single data file to each single data file, the nonvolatile memory having a data area for a reproduction management file for managing a plurality of files, each of which is composed of the blocks, and a file management area for file management information for managing the plurality of data files and the reproduction management file.
A second aspect of the present invention is a nonvolatile memory reproducing apparatus for reproducing data from a nonvolatile memory for segmenting a signal data file into blocks each having a predetermined length and adding an attribute file for managing the single data file to each single data file, the nonvolatile memory having a data area for a reproduction management file for managing a plurality of files, each of which is composed of the blocks, and a file management area for file management information for managing the plurality of data files and the reproduction management file, the apparatus comprising a first determining means for determining whether a part or all of the file management area has been destroyed, a searching means for searching each block when a part or all of the file management area has been destroyed as the determined result of the first determining means, a second determining means for determining whether or not a block searched by the searching means is the reproduction management file, a third determining means for determining whether or not a block searched by the searching means is the attribute file, and a recovering means for recovering the destroyed file management information corresponding to the searched reproduction management file and the attribute file when the first determining means and the second determining means have searched attribute files corresponding to the reproduction management file and each single data file.
A third aspect of the present invention is a nonvolatile memory reproducing method for reproducing data from a nonvolatile memory for segmenting a signal data file into blocks each having a predetermined length and adding an attribute file for managing the single data file to each single data file, the nonvolatile memory having a data area for a reproduction management file for managing a plurality of files, each of which is composed of the blocks, and a file management area for file management information for managing the plurality of data files and the reproduction management file, the method comprising the steps of (a) determining whether a part or all of the file management area has been destroyed, (b) searching each block when a part or all of the file management area has been destroyed as the determined result of step (a), (c) determining whether or not a block searched at step (b) is the reproduction management file, (d) determining whether or not a block searched at step (b) is the attribute file, and (e) recovering the destroyed file management information corresponding to the searched reproduction management file and the attribute file when attribute files have been searched corresponding to the reproduction management file and each single data file at steps (a) and (b).